This invention relates to containers and pull tab openers therefor. In particular, this invention relates to pull tab openers for containers such as aluminum beverage cans and the like, which have a tab lever whereby lifting the tab lever forces a push-in closure in the top surface of the container inwardly, and thereby opens the container for access to the interior thereof. The present invention provides an articulated pull tab opener for containers such as beverage cans and the like.
Containers having pull tab openers are generally aluminum beverage cans, but they may be other containers including some beverage cans that are made of metals or plastics, and containers that are supplied for other purposes such as dispensing various fluids in automobiles into the appropriate reservoir therefor.
However, the preponderant use of containers having pull tab openers is in the aluminum beverage can industry, particularly for such beverages as soft drinks and beer.
Indeed, an article by Hosford and Duncan entitled The Aluminum Beverage Can, published at pages 48 through 53 of Scientific American for September, 1994, discusses that the United States production of beer and soft drink containers, even at that time, was in the range of 300 million aluminum beverage cans per day, for an output of 100 billion beverage cans per year. Each one of the those beverage cans has a pull tab opener; and each one of those pull tab openers is attached to the top surface or lid of the beverage can by a rivet which is formed integrally with the lid. At the side of the rivet opposite the outer end of the pull tab is a scored opening which is a push-in closure. The closure seals the can, and withstands the pressure therein until such time as it is forced downwardly at its frangible perimeterxe2x80x94typically, in the range of about 300xc2x0 defining the push-in closure.
Over the years, the aluminum beverage can has become a very highly engineered product. As at 1994, the weight of an average beverage can had been reduced to about 0.48 oz. Great effort has been directed to reducing the mass of the can by thinning its walls, such that in 1994 it was estimated that a reduction of the mass of an average aluminum beverage can by even 1% would save approximately 20 million dollars per year (in 1994 dollars) in aluminum.
Through all of this time, however, there has been very little effort to improve the opening pull tab design. Typically, the pull tab is secured against the top surface or lid of the beverage can in an orientation which is essentially flat against and parallel to the top surface. The push-in closure is opened by lifting the outer end of the tab and pulling upwards so as to pivot the tab about the rivet. This tends to deform the lid of the surface of the can somewhat, but because of the dimensions involved, that deformation is not permanent except where the push-in closure has been broken away at its frangible outline and has been pushed or levered downwardly into the interior of the can so as to depend at an angle downwardly from the lid of the can.
This has meant that, typically, as many as 100 billion fingernails are at risk every year of being broken, while attempting to start the leverage action of the pull tab upwardly from its rest position against the top surface or lid of the beverage can. However, such circumstances continue to run almost unabated since the first aluminum beverage cans came into the market in 1958.
The present invention seeks to overcome that difficulty, by providing an articulated pull tab opener design by which individuals who have long fingernails, or weak fingers, or delicate hands, can still effect opening of the beverage can without difficulty and without risk to their fingernails or the tips of their fingers.
It must be kept in mind, however, that it is not possible to provide a pull tab which is such as to have a raised end that is present at the time that the pull tab is affixed to the lid of the beverage can. One particular reason for that is that the pull tab is rivetted to the lid of the beverage can prior to the top of the can being seamed to the body of the can in the region around the perimeter around the top of the can. Any pull tab which extends upwardly from the top surface of the can would get in the way of the seaming equipment. Of course, even with thousands of plants scattered about the country, it will be understood that each can must be filled and sealed in a minimum of time, and the provision of additional filling and seaming machines to accommodate a raised pull tab is not an option.
Further, an elevated pull tab may preclude stacking, it may get snagged by other cans during handling, and there is a risk that the score which defines the frangible edge of the push enclosure might get broken so as to cause leakage, lose pressure in the can, and so on.
The pull tabs which are provided for aluminum beverage cans are, themselves, highly engineered components. Typically, they are made with a progressive stamping dye from a thin coil of aluminum, and must stay in the punched metal strip until they are rivetted to the top of the can. Moreover, during leverage process to open the can by breaking the frangible seal and levering downwardly the push-in closure, the pull tabs must have considerable beam strength. Accordingly, pull tabs are typically formed with tubular cross-section perimeter, so that the high stress of opening the can will be withstood while, at the same time, permitting the use of thin coiled aluminum from which the pull tabs are manufactured.
Briefly, the present invention provides an articulated structure whereby the outer end of the pull tabxe2x80x94the end which is remote from the frangible push-in closurexe2x80x94can be articulated upward by being lifted to the extent that the elastic memory of the material of the pull tab is overcome, so that the outer end of the pull tab assumes a new rest position which is angled upwardly from the remaining portion of the tab in the region of the rivet. This arrangement is made possible by providing a crease line across the tab in a region behind the rivet, remote from the frangible pushxe2x80x94in closure. At that point, the thickness of the tab is the thickness of the material from which it was madexe2x80x94or thinner, as described hereafterxe2x80x94so that it may be easily bent with a minimum of effort.
However, the present invention provides for a pair or pairs of protrusions which are formed such that, when the outer end of the pull tab is articulated upwardly, faces of the protrusions come into contact one with the other so as to provide force transmission and so as to preclude further bending or articulation of the outer end of the tab about the crease line.
Thus, the outer end of the lift tab opener may be easily tilted or bent upwardly to a new rest position, after which the end or the side of a finger may typically be placed underneath the tab, with the thumb being placed on the upper surface of the tab, so as to provide the appropriate leverage action to break the frangible seal and to lever the frangible push-in enclosure downwardly, in the manner which is well known.
Apart from the Scientific American article referred to above, several patents are known which teach various kinds of can openers which employ a levering lift tab construction.
HARVEY et al. U.S. Pat. No. 3,301,434 issued Jan. 31, 1967 teaches a can opener for a can. However, the opener is connected to the lid of the can in two different places, at two different rivets. One end of the opener forms a first lever which may be lifted from its end above a recess so that it will hinge upwardly around a hinge area and, at the same time, relieve or lift a first rivet away from the lid of the can so as to reveal a vent opening. Continued lifting of the opener causes the pre-scored area at the other end of the opener to break and hinge downwardly about a second rivet. The edges of the tab, except at the hinge area, are stiffened with a rib construction.
HASEGAWA U.S. Pat. No. 4,276,993 issued Jul. 7, 1981 teaches a non-detachable tab of the sort which is generally well known. A slight depression is provided underneath the end of the tab, but its purpose is to preclude a pair of projections which are provided on the tab from arcuate sideways motion. In other words, the purpose of the depression and the pair of projections is to inhibit rotation of the tab about the rivet by which it is fixed to the lid of the container. The tab is provided with an opening through which part of the forefinger can protrude, but the finger hole is small enough that the finger cannot come all the way through, and thereby pull the tab away from the can, and breakage of the fingernail is said to be precluded.
LUNDGREN U.S. Pat. No. 5,248,053 teaches an operating lever or tab for opening a beverage container, where the lever is rotated about the rivet and the end of the lever is elevated by being forced to run up a ramp being formed in the lid of the beverage container. However, this structure requires that the ramp be formed in the container lid, and the ramp may be in the way when a seaming operation occurs to close the can after it has been filled with its beverage. Moreover, use of the operating lever is not intuitive.
A similar arrangement in many ways is taught in LUNDGREN U.S. Pat. No. 6,026,971, issued Feb. 22, 2000. Once again, a ramp is built into the surface of the lid of the container, and once again the operating lever is rotated in most embodiments that are disclosed. The Lundgren lever operated opener requires a finger opening at its distal end. It provides a flexed portion of the tubular side arms of the operating lever and, in at least one embodiment, the material of the tubular portions of the side arms is formed downwardly to become a pair of flat surfaces on either side of the controlled flex portion. A control notch is provided also in the controlled flex portion, however, to promote flexing.
In accordance with one aspect of the present invention, there is provided a container and pull tab opener therefor. Typically, as noted, the container is an aluminum beverage container, but it is not necessarily an aluminum beverage container. In any event, the container has a top surface which has a frangible push-in closure therein, the frangible push-in closure being partially severable from the top surface. The pull tab opener is secured to the top surface at a place near the frangible push-in closure.
The pull tab opener comprises a nose portion and a tail portion. At least a portion of the nose portion overlies at least a portion of the frangible push-in closure; and the place where the pull tab opener is secured to the top surface is positioned between the nose portion and the tail portion.
The tail portion is articulable, and has a front lever portion which lies in the same plane and which is an extension of the nose portion, and it also has a rear lift lever portion which is articulably joined to the front lever portion at a crease line.
The tail portion comprises a base portion and at least a pair of protrusions upstanding from the base portion. One of the at least a pair of protrusions is located at each side of the crease line.
Each of the protrusions has a front face which is subtended by and extends upwardly from the crease line. Each of the front faces is rectangular in shape. Moreover, each of the front faces is opposed to the other of the front faces of the at least a pair of protrusions.
Each of the at least a pair of protrusions has a sloped rear surface extending downwardly from the top edge of the respective front face towards the base portion, in a direction away from the crease line.
The angle formed between the opposed pair of front faces is in the range of from 10xc2x0 to 50xc2x0.
Typically, the pull tab opener is secured to the top surface by a rivet which is placed near the frangible-portion closure. In that case, the rivet is positioned between the nose portion and the tail portion.
Typically, two pairs of opposed protrusions are arranged, with one of each of the pairs of opposed protrusions being at each side of the crease line.
The perimeter of the pull tab opener is formed so as to have a tubular configuration, which extends above the base portion except in the region at each end of the crease line.
Two possibilities exist as to the height of the apex formed between the front face and the sloped rear surface of each of the at least a pair of protrusions, above the base portion. The height of the apex may be greater than the height of the tubular perimeter above the base portion, or it may be not greater than the height of the tubular perimeter above the base portion.
In a further embodiment of the present invention, the material of the base portion may be stamped in the region of the base line, so as to have a reduced thickness.
In another embodiment of the present invention, a depression may be formed in the top surface of the container in a region thereof which is below the tail portion. The crease line overlies the depression, and the length of the depression is less than the length of the tail portion.
The elastic memory of the material of the pull tab opener, in the region of the crease line, is such that when the rear lift lever portion is pivoted about the crease line so as to bring the opposed front faces of the at least a pair of protrusions into contact one with the other, the elastic memory is overcome. Thus, the rear lift lever portion is articulated to a new rest portion relative to the front lever portion.
This effect also may occur in those embodiments which include a depression in the top surface of the container. Thus, when the tail portion of the pull tab opener is pushed downwardly so as to permit the crease line to enter into the depression, and so that the rear lift lever portion is pivoted about the crease line to the extent that the opposed front faces of the at least a pair of protrusions are brought into contact one with another, then once again the elastic memory is overcome and the rear lift lever portion is articulated to a new rest portion relative to the front lever portion.
In another embodiment of the present invention, there is provided a container and pull tab opener therefor, where the container has a top surface which comprises a frangible lid which is fully severable away from the container, and where the pull tab opener is secured to the top surface near a portion of the frangible perimeter thereof.
The pull tab opener comprises a nose portion and a tail portion; and the nose portion is located in close proximity to the frangible perimeter of the lid. The pull tab opener is secured to the lid at a position on the pull tab opener which is between the nose portion and the tail portion.
The tail portion is articulable, and has a front lever portion which lies in the same plane and which is an extension of the nose portion, and it also has a rear lift lever portion which is articulably joined to the front lever portion at a crease line.
The tail portion comprises a base portion and at least a pair of protrusions upstanding from the base portion. One of the at least a pair of protrusions is located at each side of the crease line.
Each of the protrusions has a front face which is subtended by and extends upwardly from the crease line. Each of the front faces is rectangular in shape. Moreover, each of the front faces is opposed to the other of the front faces of the at least a pair of protrusions.
Each of the at least a pair of protrusions has a sloped rear surface extending downwardly from the top edge of the respective front face towards the base portion, in a direction away from the crease line.
The angle formed between the opposed pair of front faces is in the range of from 10xc2x0 to 50xc2x0.
Other features of the embodiment of the invention wherein the entire lid is fully severable away from the container are as discussed above